Electrical connector



March 3, 1964 J. R. KELLER 3,123,431

ELECTRICAL CONNECTOR Filed. July 18, 1961 United States Patent 3,123,431 ELEiCTRiEAL (IGNNECTGR Joseph R. Keller, Harrisburg, Pa, assignor to AMP incorporated, Harrisburg, Pa. Filed July 18, well, Ser. No. 124,854 in Claims. (Cl. 339 276) This invention relates to electrical connectors of the type adapted to be crirnped onto wires and particularly to the so-called flag type of connector which, after crimping, extends normally of the conductor axis. In the description which follows, the invention is particularly disclosed and described with reference to a quick disconnect type of electrical connector, however, the invention is not so limited but is adaptable to usage with other types.

US. Patent 2,774,951 shows the general features of a popular type of electrical connector which is adapted to receive a rectangular tab and which comprises in general a hoot or web having its edge portions upwardly turned and inwardly and downwardly directed towards the floor so that the tab can be inserted between the floor and the edges of the sidewalls. This type of disconnect has received a widespread acceptance in the electrical arts and is used in a variety of forms and sizes throughout the industry. The Kinkaid patent shows a conventional connector of this type having channel-shaped or trough-like ferrule-forming portions integral with the contact portion and disposed in axial alignment therewith. When a connector of this type is secured to a wire, it is merely necessary to position the stripped end of the wire in the appropriate channel-shaped ferrule-forming portion and thereafter crimp this ferrule-forming portion by bending the sidewalls inwardly towards each other and then downwardly towards the conductor. It should be added that alternative types of crimps are also employed to form the electrical connection between the connector itself and the end of the wire.

Virtually any crimping operation involves the imposition of substantial compressive stresses on the ferruleforming portions of the connector when the crimp is made and the imposition of such stresses inevitably results in an axial extrusion of this ferrule-forming portion with a concomitant elongation thereof. When the ferrule-forming portion is axially aligned with the contact portion of the connector, as in the above-mentioned Kinkaid patent, this extrusion does not present a problem since the ferrule-forming portion merely clongates rearwartlly, that is away from the contact portion of the connector, and the stres es imposed upon the ferrule-forming portion are not transmitted to the contact portion itself. However, where the contact portion extends normally of the wire after crimping and, therefore, normally of the axis of the ferrule-forming portion, this extrusion constitutes a troublesome phenomenon for the reason that since the ferrule-forming portion is integral with the contact portion, the extrusion of the ferrule-forming portion can cause transmission of stresses to the contact portion with a resulting unwanted deformation thereof. For example, the sidewalls of the contact portion may be spread apart and the critical dimensions required in this contact portion can thereby be lost. Alternatively, the imposition of the compressive stresses of a crimping operation may cause fracture in the connector in areas of high stress concentration such as sharp corners or bends if these parts fail to yield. It follows that in flag type connectors, it would be desirable to isolate the eifects of the extrusion of the ferrule-forming portion from the contact portion and to prevent any unintentional weakening or cracking of any parts of the connector when the crimping operation is carried out.

It is accordingly an object of the present invention to "ice provide an improved flag type electrical connector. It is a further object to provide a flag type electrical connector in which the contact portion and the ferrule-forming portion are joined together in a manner such that the compressive stresses imposed upon the ferrule-forming portion at the time of crimping are isolated from the contact portion. A still further object is to provide a flag type connector having a ferrule-forming portion and a contact portion which are joined together in a manner such that selective and controlled yielding takes place at the time of crimping in a predictable and harmless manner.

These and other objects of the invention are achieved in a preferred embodiment thereof comprising a flag-type disconnect having a contact portion including a web or floor with up-standing and inwardly directed sidewalls so that a conventional tab can be inserted into the contact portion. Spaced from the contact portion is a generally U-shaped ferrule-forming portion having its axis extending normally of the axis of the contact portion. These two portions of the connector are integrally formed and are joined together by means of a pair of struts one of which, in the preferred embodiment, is of L-shaped cross section so that it resists deformation or deflection when the connector is crimped. The other strut is of simple rectangular cross section and is easily bent or deflected when the crimping operation takes place. The resistance to flexure of this second strut is sufiiciently low so that it deforms upon crimping to a degree sufficient to accommodate all of the longitudinal extrusion of the ferrule-forming portion at the time of crimping. The critical contact portion of the connector is thus left undisturbed and undamaged by the crimping operation.

In the drawing:

FIGURE 1 is a perspective view of an uncrimped terminal in accordance with the invention.

FIGURE 2 is a frontal view of the connector.

FIGURE 3 is a top plan view of a pair of connectors integral with a carrier strip showing the manner in which the preferred embodiment is manufactured.

FIGURE 4 is a side view of the connector seen from the right in FIGURE 2.

FIGURE 5 is a view taken along the lines 5-5 of FIGURE 4.

FIGURE 6 is a top plan view or" the connector of FIGURE 1, and

FIGURE 7 is a View similar to FIGURE 6 but showing the connector after crimping and illustrating the bending of the deformable strut.

The preferred embodiment comprises a connector having a contact portion 2 and a ferrule-forming portion 4 oriented substantially normallyof the axis of the contact portion. The ferrule-forming portion comprises a generally fiat base section 6 having a first pair of upstanding sidewalls 8 which are adapted to receive and to be crimped onto the stripped end .of a conductor and a second pair of upstanding sidewalls 12 which are intended to be crimped onto the insulation of the conductor. Advantageously, the section 8 is provided with grooves it in order to facilitate .and improve electrical contact between the conductor and connector. The contact portion has a base or web 14 having its edge portions 16 bent to extend normally of its plane and then downwardly as shown at 18 toward the underside of the web 14 as viewed in FIGURE 1. Connectors of this type are adapted to receive simple tabs as fragmentarily shown at 2th to establish electrical contact upon insertion of the tab.

For best results, the contact portion 2 must conform to relatively precise dimensional tolerances and the contact portion .should not, therefore, be subjected to abusive treatment if its electrical integrity is to be preserved. The contact portion and the ferrule-forming portion are integrally formed and in the finished form are joined together by a pair of struts 22, 2.8. The strut 22 is of L-shaped cross section as shown in FIGURE and is, therefore, extremely stiff and resistant to flexure when it is loaded by forces applied in a direction normally of its axis. This strut 22 is joined to the contact portion 8 by means of an upwardly inclined transition section 24 which merges with the iloor of the ferrule-forming portion.

The strut 28 is of simple rectangular cross section and has its major axis extending normally of the direction of the applied forces When crimping takes place as will be explained below. By virtue of this orientation of the strut 28, it is easily and readily deformed in the same manner as a thin strip of metal can be easily flexed in a direction normal to its plane. Strut 28 is joined to the ferruleforming portion 12 by a curved transition section 26 which also merges with floor 6 of the ferrule-forming portion and is, at its opposite end, connected to the sidewall l6. Advantageously, a notch 36 is formed at the end of the strut 28 and adjacent to the contact portion to concentrate a relatively high stress in this area upon crimping and to encourage bending of this strut in a controlled manner.

In use, a wire is positioned in the ferrule-forming portion with its stripped end 36 between the sidewalls 8 and with the end portion of the insulation 38 between the sidewalls 12. Thereafter the two pairs of sidewalls are crimped onto the end of the wire, the sidewalls 8 being bent inwardly and downwardly as shown at 8', FIGURE 7, while the sidewalls 12 are simply wrapped around the insulation as shown at 12'.

The high crimping forces applied to the ferrule-form ing portion, and particularly to the wire. barrel portion 8 inevitably result in longitudinal extrusion of this portion of the connector. This in turn causes the ferrule-forming portion to elongate and, since the L-shaped strut 22 is highly resistant to deformation in the direction of this applied force, the strut 28 is bent in the manner shown in FIGURE 7 at 28. That is, as elongation of the ferrule-forming portion takes place, a high stress concentra tion at seat of notch 30 results and the strut is therefore bent from the dotted line position of FIGURE 7 to the full line position thereof. It will thus be apparent that ll of the effects of crimping, and particularly the elongation of the ferrule-forming portion, are concentrated and taken up in the single strut member 28 which deforms in a. controlled manner to accommodate the dimensional change brought about by the crimping operation. None of these stresses are transmitted to the contact portion 14 which thus remains undisturbed and unchanged through out the operation. It will be readily apparent that in the absence of this deformable strut 28, the elongation of the ferrule-forming portion would of necessity result either in the transmission of stresses to the contact portion of the connector or possibly the formation of cracks in the struts where they join te contact portion.

It will be apparent that while the extrusion of the ferrule-forming portion of the connector is taken up by bending of the strut 28 in the preferred embodiment, the same result might be achieved by flexure of this strut. Also, it might be feasible under some circumstances to permit both struts to yield or bend rather than only one strut as in the preferred embodiment.

Connectors in accordance with the invention are advantageously formed by die stamping operations and are produced in strip form as shown in FIGURE 3. In this figure, two connectors are shown secured to a carrier strip 34 by means of connecting sections 32 which are removed by shearing at the time of crimping. The present invention is not limited to the precise form of connector shown in the drawings but is amenable to usage in other flag type connectors where it is desirable to obviate the transmission of crimping stresses to the contact portion of the terminal and/ or to avoid fracture of connecting struts or other connecting members between the contact portion and the ferrule-forming portion.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

I claim:

1. A flag type electrical connector comprising a contact portion and a crimp portion, the axis of said crimp portion extending transversely of the axis of said contact portion, said portions being connected together by struts, at least one of said struts being individually deformable in a direction extending laterally of its axis by an amount substantially equal to the elongation which takes place in said crimp portion upon crimping whereby, upon crimping said crimp portion to a conductor, said crimp portion is longitudinally extruded and said one strut deforms to ac-- commodate said extrusion.

2. A flag type electrical connector comprising a contact portion and a crimp portion, the axis of said crimp portion extending transversely of the axis of said contact portion, said portions being connected together by a pair of spaced apart struts, one of said struts being yieldable upon application of a force in a direction extending transversely of its length and parallel to the axis of said crimp portion, and the other of said struts being relatively stiff and resistant to yielding upon application of a force in said direction whereby, upon crimping said crimp portion to a conductor with concomitant longitudinal extrusion thereof, said one strut yields to accommodate said extrusion without transmission of stress to other parts of said connector.

3. A connector as set forth in claim 2 wherein said one strut is of substantially rectangular cross section and said other strut is of L-shaped cross section.

4. A connector as set forth in claim 2 wherein said one strut has a notch therein at a location adjacent to said contact portion whereby said strut yields by being bent with said notch serving as a pivot.

5. A flag type electrical connector comprising a con tact portion and a crimp portion, the axis of said crimp portion extending transversely of the axis of said contact portion, said portions being connected together by a pair of spaced apart struts, one of said struts having a relatively weakened zone at a location adjacent to said contact portion whereby, upon crimping said crimp portion to a conductor, said crimp portion is longitudinally extruded and said one strut is bent with said weakened zone serving as a pivot thereby to compensate for said extrusion without transmission of stress to other parts of said connector.

6. A flag type electrical connector comprising a contact portion and a crimp portion, the axis of said crimp portion extending transversely of the axis of said contact portion, said portions being connected together by a pair of spaced apart struts, one of said struts having a stress raising notch adjacent to said contact portion whereby said one strut tends to bend with said notch as a pivot upon application of a force in a direction parallel to the axis of said crimp portion, and the other of said struts being relatively stiff and resistant to deformation and bending upon application thereto of a force in said direction whereby, upon crimping of said crimp portion to a conductor with concomitant axial extrusion thereof, said one strut is bent to compensate for said extrusion without transmission of stress to other parts of said connector.

7. A flag type electrical connector formed from a single section of sheet metal, one end of said section being formed as a contact portion of said connector, ear means struck up from said section on the opposite end of said section to provide a crimp portion of U-shaped cross section, the axis of said crimp portion extending transversely of the axis of said contact portion, a pair of connecting links disposed one on each side of said ear means,

one of said connecting links being readily deformable in a direction parallel to the axis of said crimp portion whereby, upon crimping said crimp portion to a conductor by bending said ear means over, and compressing said ear means around said conductor, said crimp portion is axially extruded, and said one connecting link is deformed to compensate for said extrusion.

8. A connector as set forth in claim 7 wherein said one connecting link has a notch adjacent to said contact portion and is deformed by being bent with said notch as a pivot.

9. A connector as set forth in claim 7 wherein the other of said connecting links has one edge thereof bent over to form an L-shaped cross section whereby said other link is still? and resistant to deformation.

10. A flag type electrical connector comprising a contact portion and a crimp portion, said contact portion comprising a web having upstanding sidewalls on its opposite sides, said contact portion being intended to receive a tab of a mating connector, the axis of said crimp portion extending transversely of the axis of contact portion, said portions being connected together by a pair of spaced apart struts, one of said struts having a relatively weakened zone at a location adjacent to said contact portion whereby, upon crimping said crimp portion to a conductor, said crimp portion is longitudinally extruded and said one strut is bent with said weakened zone serving as a pivot thereby to compensate for said extrusion without transmission of stress to other parts of said connector.

References Cited in the file of this patent UNITED STATES PATENTS 2,406,079 Krueger Aug. 20, 1946 2,701,350 Soreng Feb. 1, 1955 2,774,951 Kincaid et al Dec. 18, 1956 2,813,258 Klumpp Nov. 12, 1957 2,811,705 Schumacher Oct. 29, 1957 FOREIGN PATENTS 325,979 Switzerland Jan. 15, 1958 

5. A FLAG TYPE ELECTRICAL CONNECTOR COMPRISING A CONTACT PORTION AND A CRIMP PORTION, THE AXIS OF SAID CRIMP PORTION EXTENDING TRANSVERSELY OF THE AXIS OF SAID CONTACT PORTION, SAID PORTIONS BEING CONNECTED TOGETHER BY A PAIR OF SPACED APART STRUTS, ONE OF SAID STRUTS HAVING A RELATIVELY WEAKENED ZONE AT A LOCATION ADJACENT TO SAID CONTACT PORTION WHEREBY, UPON CRIMPING SAID CRIMP PORTION TO A CONDUCTOR, SAID CRIMP PORTION IS LONGITUDINALLY EXTRUDED 